Conventional digital transmitters include a digital-to-time converters (DTC) that modulates the LO carrier with the phase information of the signal, and a Digital Power Amplifier (DPA) that modulates the amplitude on the phase modulated LO and combines (reconstructs) the original signal. One of the challenges for digital transmitter architectures arise from wideband signals utilized in many current communication protocols, such as Wifi 802.11 ac, which have signal bandwidths ranging from 20 MHz to 160 MHz, and 3GPP LTE, which has signal bandwidths of up to 40 MHz. These wide bandwidths may require the DTC cover up to 360 degrees or more of dynamic range and a 14 bit resolution. Some conventional techniques, which use a large N-way multiplexer (MUX) and digitally controlled delay lines (DCDL), are cumbersome, slow, noisy and/or add non-linearities, resulting in poor performance and increased power consumption.
Thus there are general needs for improved DTCs can provide up to 360 degrees or more of dynamic range and a 14 bit resolution.